Drive bushing for rotary tables



Sept. 26, 1939. w, H MAXWELL 2,174,108

, DRIVE BUSHING FOR ROTARY TABLES Filed Aug. 8, 1938 2 Sheets-Sheet 1 E1. a; 39 m Sept. 26, 1939. w. H. MAXWELL DRIVE BUSHING FOR ROTARY TABLES Filed Aug. 8, 1938 2 Sheets-Sheet 2 Patented Sept. 26, 1939 UNITED STATES PATENT OFFICE Application August 8, 1938, "Serial No. 223,577

10 Claims.

This invention relates to well drilling equipment and relates more particularly to bushings for use in the rotary tables of well drilling rigs. A general object of this invention is to provide an improved drive 'or kelly bushing of the class embodying rollers for contacting the drive stem or kelly of a well drilling string. 7

In the rotary method of well drilling a rotary table is provided in the derrick to drive or rotate :10 the drilling tools. A drive stem or'kelly or polygorial cross section is provided on the upper end of the well drilling string and a drive bushing is arrangedin the rotary table to contact the kelly to transmit rotation from the rotary table to the :15 drilling string. The engagement of the bushing with the kelly is such that the kelly may be fed vertically while being rotated. Considerable friction and wear occur between the bushing in the rotary table and the kelly.

12 Drive bushings having rotatable rollers forengaging the faces of the kelly are usedl'to reduce the wear and friction. The rollers of such bushings are usually supported to rotate about vertically'spaced horizontal axes so that they contact the kelly at vertically spaced points, If the spacing of the rollers is uniformthe rollers have a tendencyto track one after the other-in engaging with the kelly, causing a series of impressions or'corrugations to occur inthe kelly. Cohtinued'engagement of the rollers in the corrugations increases the corrugations causing "material damage. H

Another objectof this invention is to provide a drive bushing for use in a rotary table that does 5 not groove,corrugate, or otherwise mar ordistort the drive stem or kelly. g

Another object of this invention is to provide "a drive bushing embodying rotatable rollers for contacting the drive "stem or kelly that are ar- 40 ranged and related so that they cannot track one after the other in their engagement'with the kelly and, therefore, do not form corrugationsor grooves in the kelly, u 7

Another object of this invention is to provide 45 a drive bushing oi the character mentioned in which the turning forces on the several faces of the polygonal kelly are maintained substantially equal so that the bushing has no tendency to bend 'or warp the kelly. v H

: 'Another object of this invention is to provide a drive bushing of the character mentioned in which the rollers are arranged in vertical series and the adjacent rollers of each series are rotatable about non parallel axes, so that they cannot track in their contact with the kelly iaces.

Another object of this invention is to provide a drive bushing of the general character mentioned embodying novel'm'eans for mounting or supporting the kelly contacting rollers.

A further object of this invention is to provide '6 a bushing of the character mentioned in which the disposition or inclination of the rollers may be easily changed from time to time as conditions'may warrant. I v

The various objects and features of my inven- 10 'tion will be fully understood from the following iletaile'd description offa typical preferred form and application of the invention, throughout which description reference is made to the accompanying drawings, in which: v

-Fig; 1 is'a side elevation of the improved bushing of the present invention "engaging about a 'drill'ster'n or kelly and arranged in a typical rotarytable, illustrating the rotarytable in vertical crosssection. Fig. 2 is a top or plan View of the bushing arranged in the table, showing the kelly 'inhoriiontal cross'section. Fig. 3 is an enlarged vertical detailed sectional view of the bushing removed from the table. Fig. 4 is 'a horizontal 'detailedsectional View taken as indicated by line l-Jon 3. Fig. 5 is atop or plan View of one of theea'ges and its rollers removed from the bushing body and Fig. 6 is an enlarged vertical detailed sectional view taken as indicated by line 6 6 on Fig. 5. 7 F I The bushing structure of the present invention is intended primarily for use inthe rotary table 'of awell drilling rig to engage and drive the drill stem orkeny or the drilling string. In the drawings I have shown a typical preferred form of the invention used in a typical rotary table .to drivea typical polygonal kelly. It is to be understood that the invention may be embodied in forms "for use in other types ofrotary tables and I, for cooperating with kellies of different cross sectionalconfiguration s.

The typical well drilling equipment illustrated in the drawings includes a rotary table T supported by bearings l0 to rotate about a vertical axis. The table T has 'a central vertical opening II receiving a master bushing I2. The master bushing I2 turns with the table and has a central vertical opening 13. The upper portion of the opening "I3 is square or polygonal and the major portion of the opening I3 is tapered as clearly illustrated in Fig. 1 A gear l4 meshes with teeth [5 on the under side of the table T to rotate the table. "-Figs. l and ,2 of the drawings illustrate a typical kelly K of substantially square horizontal cross section extending vertically through the table T and its bushings.

The improved drive bushing of the present invention includes, generally, a body l6 for arrangement in the master bushing l2, cages [1 in the body 16, series or sets of rollers E8 in the cages l1 for contacting the kelly K and means l9 rotatably mounting or supporting the rollers I8 in the cages l1.

The body It is provided to contain the cages l1 and their rollers 18 and is shaped to be received in the opening l3 of the master bushing l2. The body I6 is a tubular member having a tapered lower portion 20 for fitting the tapered portion of the opening [3 and having a square or polygonal portion 2| for fitting the square upper portion of the opening l3. The body I6 is of substantial length and projects upwardly beyond.

the upper surfaces of the master bushing l2 and the table T. A cylindrical externally threaded portion 22 is provided at'the upper end of the body IS. The major portion of the opening in the tubular body I6 is generally square in horizontal cross section having four major walls 23. The walls 23 are substantially vertical and the adjacent walls 23 are disposed at to one another. Diagonal corner walls 24 extend between and connect the adjacent major walls 23. An inwardly projecting horizontal shelf or annular flange 25 is provided in the body 16 at the lower ends of its walls 23. The central opening26 of the flange 25 is adapted to pass the enlarged end portions (not-shown) of the kelly K with suitable clearance.

The cages H are frame-like parts provided to carry the rollers l8 and their mounting means l9. In the form of the invention illustrated there are four cages l1 fitted or arranged in the tubular body I 6. The four cages 11 may be alike or identical and each includes two spaced vertical sides 21 and a bottom 28. A top'29 is provided for each cage l1 and is secured to the upper ends of its sides 21 by screws 30. The cages I1 are adapted to be inserted in the body 16 from its upper end to have their bottoms 28 rest on the body flange 25. The outer surfaces of the cage sides 21 are adapted to engage againstthe main body Walls 23. The diagonal corner walls 24 assist in locating the cages l1 in the body 16. The cages 11 preferably have interfitting or nesting portions to assist in holding them in place. i Thetrailing side 21 of each cage l1, relative to the right hand direction of rotation, has a vertically. extending notch or groove 3| in its inner portionreceiving the inner corner portion of the advancing side 21 of the adjacent cage l1. The corner portions of the cages l1 fitting the grooves 3| assist in locating the cages in the body l6 and hold the cages against inward displacement and relative lateral shifting.

The rollers I8 are simple elongate roller elements having cylindrical external surfaces for contacting the fiat vertical faces of the polygonal kelly K. The kelly contacting rollers l8 are tubular having central longitudinal openings 33. In accordance with the invention the several rollers l8 embodied in the bushing may be alike in size and shape. There is preferably a plurality of rollers l8 carried by each cage l1. In the form of the invention illustrated there are four rollers l8 carried by each cage 11.

The means IQ for mounting or supporting the rollers 18 in the cages l1 are important features of the invention. The means l9 support the rollers 18 in the cages [1 in such a manner that the sets or pairs' of blocks in that cage 11.

The roller supporting means l9 include supporting shafts or pins 34 for carrying the rotatable rollers IB. The pins 34 extend through the openings 33 of the rollers l8 and are sufficiently long to project beyond the opposite ends of the rollers. In practice the supporting pins 34 may be simple elongate members of uniform length.

The roller supporting means I9 further include blocks 35 arranged in the cages l1 to carry the projecting end portions of the pins 34. The blocks 35 are arranged in vertical grooves 36 in the inner surfaces of the cage sides 21. The grooves 36 extend downwardly from the upper ends of the cages l1 and terminate at or above the bottoms 28 of the cages. In the preferred construction the grooves 36 have flat vertical walls and the two grooves 36 of each cage l1 are directly opposite one another.- The supporting blocks 35 are proportioned to correctly fit the grooves .36 and are adapted to be introduced into the grooves at the upper ends of the cages I1. In the preferred construction the blocks 35 are alike in size and shape and are generally rectangular members. Where each cage l1 carries four rollers l8 there are four blocks 35 arranged in each groove 36. The blocks 35 are supported one upon the other and the lowermost blocks 35 bear or rest on the bottom walls of the grooves 36. The blocks 35 are proportioned so that the tops of the uppermost blocks 35 are substantially flush with the upper surfaces of the cages I1. The tops 29 of the cages l1 may serve to retain the supporting blocks 35 in the cages.

Each block'35 has a transverse socket or opening 31 for receiving a projecting end portion of a roller supporting pin 34. The openings 31 are preferably spaced midwayrbetween the upper and lower ends of their respective blocks 35. An inwardly projecting boss 38 is provided on the inner side of each block 35 around its opening 31. The disposition and relation of the openings 31 in the pairs of horizontally opposing blocks 35 of i a cage l1 are suchthat the pins 34 supported therein and the rollers l8 carried by the pins have non-parallel longitudinal axes. The openings 31 of each pair of horizontally aligned blocks 35in a cage l1 may have an inclination or direction diflferent from the openings 31 in the other In the particular case illustrated in the drawings the lower blocks 35 of each cage l1 have horizontal openings 31, the blocks 35 resting on the lower blocks 35 have openings 31 sloping in one direction, the third to the lowermost blocks 35 have openings 31 sloping in the otherdirection, and

the uppermost blocks 35 have openings 31 sloping in the same direction as the second to the lowermost blocks 35. The openings 31 that are inclined preferably have the same degree of inclination; and the blocks 35 provided with the inclined openings therefore may be identical. It

is to be understood that the lowermost blocks 35 of a cage 11 may have inclined openings 31 and tudinal axes lying in a common vertical plane so that the rollers I8 supported on the pins 34 may all engage the opposing flat face of the polygonal kelly K. The active or inner faces of the bosses 38 are normal to the longitudinal axes of the openings 31 which they surround and serve to limit endwise movement of the rollers I8. As illustrated in the drawings the projecting end portions of the roller supporting pins 34 may be directly carried in the openings 31 of the blocks 35.

From the above description of the relationship of the openings 31 in the stacked blocks 35 it will be seen that the rollers I8 are supported so that the adjacent rollers of a series or set are rotatable about non-parallel or angularly related axes. In this connection it is to be understood that the rollers I8 preferably rotate on their pins 34 although, if desired, the pins 34 may rotate in the openings 31 and the rollers I8 may be suitably fixed to the pins. The corresponding rollers I8 of the several cages II may rotate about axes having the same direction or inclination, or, if desired, the corresponding rollers I8 of the several cages I! may be supported to rotate about axes having different directions or inclinations. As best illustrated in Fig. 4 of the drawings the rollers l8 supported as described above project inwardly from their cages I! to have their peripheries contact the flat faces of the kelly K for the transmission of turning forces to the kelly. It will be observed that the rollers I8 projecting from the inner sides of the cages I'I substantially define a square opening for receiving a square kelly.

The principal or heavy turning forces applied to the kelly K are transmitted to the forward corner portions of the kelly relative to the righthand direction of rotation and it is preferred to arrange the rollers I8 to project to or beyond the advancing forward corners of the kelly. As best illustrated in Fig. 4 of the drawings the rollers I8 are mounted in the cages IT to have their transverse medial planes offset forwardly from the central diametrical planes of the bushing body IS with respect to the right-hand direction of rotation. This disposition or location of the rollers I8 provides for the projection of the rollers to or beyond the forward corners of the kelly K assuming the kelly to be turning in a righthand direction.

It is believed that it will be apparent how the blocks 35 may be assembled on the projecting end portions of the roller-supporting pins 34 and how the assemblies of the blocks, pins and rollers I8 may then be introduced in the cages I'I. Following the arrangement of the rollers I8 and their supporting pins 34 and blocks 35 in a cage I! the top 29 is secured to the cage and the cage is introduced in the bushing body l6. Tapered sockets 38 may be provided in the cage tops 29 to receive lifting tools (not shown) for facilitating the handling of the cages. When the several cages I! have been arranged in the bushing body I6 a ring 39 is threaded on the upper portion 22 of the body I6. The ring 39 has an inwardly projecting annular flange 40 adapted to cooperate with the tops 29 of the cages I! to hold the cages in position. The ring 39 preferably has projecting lugs 4I adapted to be brought in registration with similar lugs 42 on the bushing body I8. Bolts 43 are adapted to be passed through openings in the registering lugs M and 42 to secure the ring 39 in place. If desired the ring 39 may be split at 44 and may be clamped onto the body portion 22 by a clamping screw 45.

It is believed that the use or operation of the improved kelly bushing of the present invention will be readily understood from the foregoing detailed description. Assuming that the body I3 is seated in the master bushing I2 and that the kelly K extends through the bushing, the engagement of the rollers I8 with the kelly provides for the transmission of rotation to the kelly. As the table T is rotated the rollers I8 engaging the flat faces of the polygonal kelly transmit the torque or turning forces to the kelly. The rollers I8 being independently rotatable allow the kelly K to move vertically as it is rotated. As described above, the rollers I8 of a vertical series or set in a cage H are related so that they cannot track one after the other in their engagement with the kelly K. Thus in the event that heavy turning forces cause one of the rollers I8 to make an impression in a face of the kelly K the adjacent roller I8 will not engage in this depression as the kelly is fed vertically. The rollers I8 being supported to rotate about angularly related axes cannot groove or corrugate the kelly K to any substantial extent and, therefore, do not injure or cause warping of the kelly. The rollers I8 are supported in their cages H by simple, dependable means. The supporting blocks 35 and the pins 34 may be removed for replacement and, if desired, or believed necessary, the blocks 35 may be inverted from time to time to change the angular disposition and relationship of the rollers I8.

Having described only a typical preferred form and application of my invention I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. A rotary table bushing for driving a polygonal kelly comprising a body to be carried by the table to rotate therewith and having an opening passing the drill stem, supporting cages in the body opening, vertically spaced rollers in each cage for contacting the kelly, and means supporting the rollers in the cages for rotation about angularly related axes, said means including supporting pins for the rollers, and block members in the cages having openings carrying the pins.

2. A rotary table bushing for driving a polygonal kelly comprising a body to be carried by the table torotate therewith and having an opening passing the drill stem, supporting cages in the body opening, vertically spaced rollers in each cage for contacting the kelly, and means supporting the rollers in the cages for rotation about angularly related axes, said means including supporting pins for the rollers, and superimposed block members in the cages having openings carrying the pins, the openings. in the adjacent block members being in angular relation.

3. A rotary table bushing for driving a polygonal kelly comprising a body to be carried by the table to rotate therewith and having an opening passing the drill stem, supporting cages in the body opening, vertically spaced rollers in each cage for contacting the kelly, and means supporting the rollers in the cages for rotation about angularly related axes, said means including supporting pins for the rollers projecting from the opposite ends of the rollers, and spaced stacks of blocks in the cages having openings carrying the projecting end portions of the pins, said openings in the adjacent blocks of the stacks being in angular relation.

4. A rotary table bushing for driving a polygonal kelly comprising a body to be carried by the table to rotate therewith and having an opening passing the drill stem, series of rollers for contacting the faces of the polygonal kelly for the transmission of turning forces to the kelly, supporting pins for the rollers projecting from their ends, and spaced rows of block members supported in the body and having openings carrying the projecting portions of said pins.

5. A rotary table bushing for driving a polygonal kelly comprising a body to be carried by the table to rotate therewith and having an opening passing the drill stem, series of rollers for contacting the faces of the polygonal kelly for the transmission of turning forces to the kelly, supporting pins for the rollers projecting from their ends, and spaced rows of block members supported in the body and having openings carrying the projecting portions: of said pins, said openings of the adjacent members of a row being in angular relation whereby the adjacent rollers of a series are rotatable about angularly related axes.

6. A rotary table bushing for driving a polygonal kelly comprising a body to be carried by the table to rotate therewith and having an opening passing the drill stem, series of rollers for contacting the faces of the polygonal kelly for the transmission of turning forces to the kelly, supporting pins for the rollers projecting from their ends, and stacks of blocks supported in the body, said blocks having openings carrying the projecting end portions of the pins, the openings in the adjacent blocks of the stack being angularly related whereby the rollers are supported for rotation about non-parallel axes.

7. A rotary table bushing for driving a polygonal kelly comprising a body to be carried by the table to rotate therewith and having an opening passing the drill stem, cages inserted in the body, each cage having spaced opposing grooves, rollers in the cages, supporting pins for the rollers projecting from their opposite ends, and blocks in the grooves having openings carrying the projecting end portions of the pins to support the rollers for engagement with the faces of the kelly.

8. A bushing for use in a rotary table to drive a generally vertical drill stem comprising a body to be carried by the table and having an opening for passing the stem, a plurality of sets of rollers in the body for contacting the stem, and means supporting the several rollers of each of the said sets to have their axes of rotation parallel with a generally vertical plane and to extend transversely of the vertical axis of the stem in angular relation to one another whereby the lines of contact of their peripheries with the stem are non-parallel and one above the other.

9. In combination with the body of a rotary table bushing, a plurality of rollers in the body for contacting a drill stem, the rollers being spaced one above the other, and means for supporting the rollers in the body for rotation about axes that are parallel with a generally vertical plane and that extend transversely of the vertical axis of the stem in angular relation to one another.

10. A unit for use in the body of a rotary table bushing comprising a supporting cage, vertically spaced pins, rotatable rollers carried by the pins, and means mounting the pins in the cage to be parallel with a vertical plane and to extend transversely of a vertical axis in angular relation to one another whereby the lines of contact of the rollers with a vertical drill stem are vertically spaced and non-parallel.

' WILLIAM H. MAXWELL. 

